D,L-2-amino-4-(hydroxymethylphosphinyl)-butanoic acid (in the below, it is abbreviated as DL-AMPB) is a known compound having herbicidal activity, and used as an efficient herbicide having a wide range spectrum (see patent document 1).
However, the herbicidal activity of the DL-AMPB is about a half of that of L-2-amino-4-(hydroxymethylphosphinyl)-butanoic acid (in the below, it is abbreviated as L-AMPB), and it has been confirmed that its activity is due to L-AMPB itself (see patent documents 2 and 3). Therefore, it is highly desirable to develop a method for producing L-AMPB selectively and efficiently.
Conventionally, a method by utilizing microorganisms and enzymes (a), an asymmetric synthesis method (b) and the like are known as a method for producing L-AMPB. For example, a method for producing L-AMPB from 4-(hydroxymethylphosphinyl)-2-oxobutanoic acid by trans aminate enzyme (patent document 4), a method for producing L-AMPB from N-acetyl-DL-AMPB by enzymatic racemic division (patent document 5) and the like are disclosed as the method of (a). However, there are problems such that any of these methods need to be reacted with low concentration of basic material, a post-treatment and a purification process are complicated, further, expensive optically active amino acid must be used with more than the same mole ratio in a trans aminate reaction, and the like. For example, a method for producing L-AMPB from (R)-3-isopropyl-2,5-dialkoxy-3,6-dihydropyrazine by alkylation (patent document 6, non-patent document 1), a method for stereospecifically transforming L-vinylglycine into L-AMPB (non-patent document 2) and the like are disclosed as the asymmetric synthesis method of (b). However expensive optically active amino acid, such as like D-valine, L-vinylglycine and the like must be used as starting raw materials in these methods, and there is a problem in regard of supplying raw materials in large quantities at low cost. In addition, for example, a method for producing L-AMPB by asymmetric hydrogenation of 2-acetamide-4-(hydroxymethylphosphinyl)-butanoic acid (patent document 7, non-patent document 3) is disclosed as the asymmetric synthesis method. In this method, the asymmetric hydrogenation is performed using a rhodium catalyst, for which optically active diphenylphosphine compound is a ligand. However, there is a problem that expensive rhodium metal is used.
A synthesis of DL-AMPB by Strecker reaction has been already reported (patent document 8). However, there is no report that L-AMPB has been obtained selectively by an asymmetric Strecker reaction. On the other hand, the asymmetric Strecker reaction, in which optically active amino acid is synthesized from aldehyde, has been well known (non-patent document 4, non-patent document 5). However, cases where the high selectivity is obtained are limited to a case using arylaldehyde as a basic material, there are few examples that high selectivity is obtained in reactions to form an aliphatic aldehyde with straight chain. Moreover, there is almost no example in the asymmetric Strecker reaction to form aliphatic aldehyde with straight chain having substituted group with polarity like phosphate, also almost no example has been reported that the high selectivity is obtained.    Patent document 1: JP Kokai Publication 52-139727    Patent document 2: JP Kokai Publication 55-000025    Patent document 3: JP Kokai Publication 59-219297    Patent document 4: JP Kohyo Publication 2003-528572    Patent document 5: JP Kohyo Publication 2003-505031    Patent document 6: JP Kokai Publication 62-132891    Patent document 7: JP Kokai Publication 62-226993    Patent document 8: WO99/09039    Non-Patent document 1: Tetrahedron Lett. 1255 (1987)    Non-Patent document 2: Tetrahedron 8263 (1992)    Non-Patent document 3: J. Org. Chem. 56, 1783 (1991)    Non-Patent document 4: Chem. Rev., 103, 2795-2827 (2003)    Non-Patent document 5: J. Am. Chem. Soc., 124, 10012-10014 (2002)